/* This Arduino Project Calculates RPM of any DC Wheeled Motor

Before attempting this project try to get some knowledge about

IR Proximity Sensor module. For this project you will need a dc motor

and wheel with **half black and half white** template on the wheel rim.

Main concept of IR Tachometer is transmission and reflection of IR signal.

Abhyuday Tripathi*/

long t ; //declaring global vaiable for time to complete half rotation.

const int out = 7; //IR OUT is set to digital Pin 7.

float rpm; //declaring RPM

void setup()

{

pinMode(out, INPUT); //initialising OUT as INPUT.

Serial.begin(9600); //Activating Serial Connection at 9600 baud.

}

void loop() {

t = pulseIn(out, LOW);// calculating time for which out stays LOW.

rpm = 60000*0.5*1000/t ; //calculating RPM by keeping in mind that default time unit in Arduino is in Microseconds.

Serial.print("RPM : "); //Printing results on the Serial Monitor with interval of 1 second.

Serial.println(rpm);

delay(1000);

}